Two Gulfstream jets carrying 15 Saudis landed at Istanbul's Ataturk Airport before dawn on the day last week that Washington Post contributor Jamal Khashoggi entered the Saudi Consulate and vanished. The men checked into hotels and left Turkey later that night.

Turkish media, which released surveillance camera video of the men on Wednesday, said they were members of an elite Saudi "assassination squad," sent to kill Khashoggi.

The 59-year-old Khashoggi, a former newspaper editor in Saudi Arabia, left the country last year. He advised Prince Turki al-Faisal, former Saudi intelligence chief, and has also been close to billionaire investor Prince Alwaleed bin Talal.

In his columns in the Washington Post, Khashoggi had been escalating his criticism of Crown Prince Mohammed bin Salman.

Khashoggi was last seen on Oct. 2 entering the Saudi consulate in Istanbul to get documents for his forthcoming marriage. His fiancée, waiting outside, said he never emerged and Turkish sources said they believe Khashoggi was killed in the building.

One of the 15 Saudis identified by name and photo in the report by Sabah newspaper is a forensic expert who has worked at the Saudi Interior Ministry for 20 years, according to a LinkedIn profile and Saudi media, and serves on the board of the Saudi Society of Forensic Medicine. It alleged that he may have been responsible for cleaning up any incriminating evidence.

Other names and photos of the 15, who Sabah said travelled on diplomatic passports, match officers in the Saudi Army and Air Force, as identified by previous Saudi media reports and in one case a Facebook profile.

The footage shows some of the Saudis leaving a hotel and Khashoggi entering the consulate, walking past a black Mercedes van with diplomatic plates parked adjacent to the entrance. An hour and 54 minutes later, according to the time stamp, a black Mercedes van drives about 2 kilometres (1.2 miles) to the consul's home, where it was parked in a garage.

The footage all seemed to come from surveillance cameras, which would have been located throughout the neighbourhood housing the Saudi Consulate and other diplomatic missions. No footage has emerged of Khashoggi leaving the consulate.

The Hurriyet newspaper and other media alleged that the Saudi Consulate's 28 local staff were given the day off Oct. 2 because a "diplomats' meeting" would be held there on that day. The reports did not cite a source and there was no official confirmation.

Turkish President Recep Tayyip Erdoğan has not accused Saudi Arabia of being responsible for Khashoggi's disappearance but has said that if the Saudis have video footage of him leaving the consulate, they should release it.